Changes the timing or angle of the wave phase to encode data.
Because the wireless spectrum is a shared resource, multiple users must be able to communicate simultaneously without destroying each other's signals. This is achieved through multiplexing and multiple access techniques. The Evolution of Multiple Access
: Small objects like rain or leaves split the signal into many directions.
The PDF walks you through the historical evolution of modulation: wireless communications from the ground up pdf
Throughout this journey, the author aims to answer the "why" behind the algorithms. He notes that while masters like fred harris and Michael Rice covered the "how" and "what," his goal is to provide the "why" that leads to those satisfying "aha!" moments.
Occurs when a wave hits an object larger than its wavelength (e.g., the surface of the Earth, buildings, or walls).
: The author provides visual explainers for topics like Sampling and Aliasing on his YouTube channel. Book | Wireless Pi Changes the timing or angle of the wave phase to encode data
Used in 4G, 5G, and Wi-Fi 6, OFDM is explained as a clever trick to turn a “bad” frequency-selective channel into many “good” flat channels using the Fast Fourier Transform (FFT).
: Radiates and receives signals equally in all horizontal directions.
: Number of wave cycles per second, measured in Hertz (Hz). The Evolution of Multiple Access : Small objects
Signals face path loss, shadowing, and reflection, refraction, or diffraction off obstacles (multipath propagation).
: Physical distance between two consecutive wave peaks.
In the second edition, the book expands to cover more advanced synchronization topics, including carrier phase recovery, frequency recovery, and symbol timing synchronization, as well as orthogonal frequency division multiplexing (OFDM) and complete transceiver architecture. One reader noted that the author “successfully answered ‘Why’ of communication systems in an unprecedented detail”.
